Control system



March 19, 1935. MI SULTZER E -r AL 1,994,624

CONTROL SYSTEM Filed Jan. '7, 1933 INVENTORS ATTORNEY c Patented Mar. 19, 1935 UNIT-Eo territori FME n i CONTROL SYSTEM.'

Application January 7, 1933, Serial No. 650,733

` 7 crains.V wieso-.27) t n This invention relates to novel methods and apparatus for Yactuating relay systems or work circuits or the like. More particularly,`this invention relates to arrangements for operating a A relayv system or work circuit or the like only when the voltage in an'associated circuit equals or exceeds a predetermined value.

It has/been discovered that a relay' systemy or u work circuit or the like'may be operated and con- Io trolled by the now of current through an associated circuit by interposing lbetween the relay systemorfwork circuit and the associated circuit a tube fof any wellknown type which will act as a trigger device. When a cold cathode tube of the glow discharge type is employed for this purpose, the voltage present in therelay circuit or the work circuit maybe greater than the yvoltage which will normally produce a glow discharge be- 20 the tube willtherefore ber continually operated.

Hence the' associated circuit will beunable tocontrol the relay system or work circuit as desired. In order to vovercome this condition it is proposed to connectl between the relay system or 25 work4 circuitand the associated control circuit ages-filled tube of the hot cathode'type in addition to a gas-nlled cold cathode discharge tube of a'gasleoustype.' i 1 invention will be better understood from 30 the detailed descriptionv 'hereinafter following when read in" connection with the accompanying drawing', 'inrrlw'hich Figure 1 shows one embodiment ofV this invention given merely'for the pury pose of illustration and Fig. 2 shows another em- 35 bodirnent of the yinvention having threev associated control circuits, any one of which, when impressed with a voltage which isequal to or ygreater than some predetermined value, will cause the relay arrangement or work circuit to o becomeoperated. i

Referring to Fig. 1 of the drawing, reference character L1 designates an input circuit over v which signals or other currents may how. The .Q circuit L1 is connected to the primary winding of the transformer T,` the .secondary winding of which is connected to twoof the electrodes, cathodes F1 and F2, or the cold cathode gas-filled tube N which includes, yin addition to thetwo cathodes F1 and F2, a third electrode which `is an anode designated A.. The midpoint of the secondary winding `of the transformer T isconnected through a key or switch W1 to the gridelectrode G of( a hot cathode gas-filled tube desig-` nated V. The switch Wi may be of any form of open circuiting device. The tube V includes, in

tween the electrodes of the cold cathode tube andaddition to the grid G and 'anode A, cathode K and a heater H. The heater H is supplied with heating current from a battery or kother source of potential designated B1. The grid G of the y tube V is connected to the cathodeK of that tube 5 through a resistance R1 and a battery B2, the positive terminal of which is connected to the cathode K of tube V and the negative terminal to the lower terminal of the resistance R1. `The n midpoint of the secondary winding `of the transformer T is connected to the upper terminal of the resistance R1 through the key or switch W1. A relay arrangement or work circuit or other form of load'designated L2 is connected between the anode A ofthe tube V and the cathode K of that tube through a battery, or otherdirect current source of voltage designated B3. The negative' terminal of thebattery B3 is connected to the cathode K of tube V while its positive terminal extends to the relay arrangement or load L2. The battery B2 may consist of a pluralityof cells connected in series as is the case in the ordinary storage battery, and the positive terminal of any one of these cells in the series may be connected al to the anode A of the cold cathode gas-filled tube N. It' will be `obvious,'however, thata poten-` tiometer may if desired be bridged across the battery B3 and that the movable arm of the potentiometer may be directly connected to the anode A of the tube N. It will be apparent also that the key or. switch designated W2, which is interposed between the positive terminal of the battery B3 and thev relay arrangement or work circuit L2, may be employed to disconnect the circuit between these elements whenever desired. Whenever an alternating potential is impressed upon theprimary winding of the transformer T, as would be the case if` an alternating potential were transmitted 4over the input circuit L1, a corresponding alternating potential will be irnpressedacross the secondary winding of the transformerv'I, and the magnitude of this potential will depend on the ratio of the number of turns in the secondary winding to that in the primary f winding. In the arrangement shown in the draw.- 45 ing the secondary winding will preferably have a greater number of turns than the primary and consequently the voltage across the secondary winding will be greater than that transmitted over line L1 to the primary Winding of the trans- 50 former T. Moreover, a discharge will occur be-` tween the cathodes F1 and F2 of the tube N when the voltage across the secondary winding .of the transformer T is sufcient to break down the ionized gap between these cathodes. The gap between the anode A of tube N and either of the cathodes F1 or F2 may be broken down when the voltage across the secondary winding of transformer T and the voltage of batteries B2 and B3 is greater than the break-down voltage between the anode and these cathodes. The gap between cathode F1 and the anode A will be broken down during one-half of the cycle and the gap between the anode A and the cathode F2 will be broken down during the other half of the cycle.

When any one of the gaps of the tube N becomes broken down, ionization of thergas contained within the tube will take place and the impedance within the tube between theanode and either oi thecathodes will be reduced from an exceedingly high or infinite value to a comparatively low and predetermined value. By virtue of this reduction in the impedance within the tube N, a substantially large current will flow through the circuit which includes batteries B2 and B3, the anode A of tube N, and either or both of its cathodes F1 and F2, the secondary winding of the transformer T, the key W1 and the resistance R1. This current will cause a substantially large drop in potential across the resistance R1.

'Ihe grid G of the tube V is normally biased to a substantially high negative voltage by the battery B2. Because oA this high biasing voltage only avery high voltage resulting from` adrop across the resistance R1 will produce a flow of current in the output circuit of the tube V. The re sistance R1 is of such magnitude with respectto the voltagesof the batteries B2 and B3 and the linternal lvoltage drop of the tube N that the voltage drop acrossthe resistance R1 will be suiiiciently large and possibly greater than that re quired to overcome the normal bias' of the grid V so that only comparatively large voltages produced by the drop across the resistance R1 will be suiiicient to ionize the gas of the tube V and bring about the operation of the work circuit connected between the anode A and cathode K of thetube V. If a very small biasing voltage were employed in this grid circuit, a voltage of comparatively small magnitude might be sufficient to ionize the gas within the tube V and bring about the operation of the work circuit L2 even when none of the discharge gaps ofk the tube Ncwere broken down. The latter ,undesirable condition can arise from the great sensitivity of the tube V, and it must, therefore, be avoided. Thus, it will be seen that the use of the largenegative bias of the grid circuit in the tube V as is used in the circuits of this invention renders the operationof the tube V more stable and free from false operation due to minor or transient effects.

In the arrangement shown in Fig. 1,` the re- 5 sistance R1 is one of comparatively small magnitude. Inasmuch as this resistance couples the cold cathode gas-filled tube N to the hot cathode gaslled tube V, the low magnitude of coupling resistance will increase the stability of operation ofthe circuits and render the circuits Vfree from false operation due to minor or transient effects.

The arrangement shown in Fig. 1 of the drawing may be restored to its initial condition in several ways, as will now be shown. The keys W1 and W2 may be both opened, or the potential of the battery B3 may be reduced sufficiently so that the eiective potential applied to the anode A o1' the tube N will be less than the normal sustaining voltage of the tube N, thereby preventing any discharge between the cathodes and anode A of tube N from being sustained. It will be apparent also that the reduction in the Voltage of the battery B3v for restoring the circuit to its initial condi-- tion must also be suiiicient to reduce the potential between the cathode K and the anode A of the tube V below the voltage required to sustain the glow between these elements of the tube.

A resistance R2 shown in dotted lines may be inserted in series between the upper terminal ofv the resistance R1 and the grid G. of Ythe tube V by opening the circuit of the conductor, as indicated by X in the drawing. This will permit a glow discharge to occur largely between the Acathode Kand anode A of the tube V. The re- L1, L4 and L5 which may under ordinary condi.

tions be independent of each other. The inp'ut circuit La is connected to the cathodes F1 and F2 of tube N3 through the transformer T3, the circuit L4 is connected to the cathodes ,F1 and F2 of the tubeNi through the transformer. T4,

andthe circuit Lais connected to the cathodes F1 and F2 of the tube N5 through the transformer. T5. Each of the Atubes N3, N4 and N5 is preferably a cold cathodeglow discharge tube of the type y shown. in Fig. 1 and designated N lthereimand each of these tubes includes, in 'addition to two cathodes, a third electrode which is an. anodey ,v

designated A. p

The midpoints of the secondary windings ofthe transformers T3,.T4 and'Ts' are connected to veach other through the common conductor C1 and this conductor is connected to the upper terminal of the resistance R1. The lower terminal of the' resistance R1 is connectedto the negative ter-1.

Moreover, the upper minal of the batteryB2.

terminal ofthe resistance R1 may berdirectlycon-f.

nected to the grid of thetube V or it may, if -desired, be connected to the ygrid Gthrough the resistance R2 as shown also in Fig. 1 and'described hereinabove. The anodes, each designatedAgjoi! the tubes N3, N4 and N5, are connected together through a common conductorC2 and this conductor extends to the movable contact associated with the battery B3 through the key or switch W1'.

The presence'of a substantial alternating current voltage in any one of the input circuits L3', Liand L5 will be transmitted through the correspending transformer T3, T4 and T5, respectively,

and cause the gas in any one of the corresponding tubes N3, N4 and N5 to become ionized so thatv the impedance between either of the cathodes or the ionized tube and theanode will be reduced from a very high or innite value to a low and predetermined value. When the impedance between the anode and anyone of the cathodes of the tubes N3, N4 or N5 becomes so reduced,v a voltage will be impressed across the resistance R1 as described hereinabove in connection with upon the grid G of thetube B, thereby causing a glow discharge to occur between the cathode K and the anode A of the tube V. `When this oc-A curs, the battery B3 will transmit a substantially large current to the relay apparatus or work circuit designated L2. As in the case of Fig. 1, the circuits of Fig. 2 may be restored to their initial condition either by opening both of the keys W1 and W2 or by substantially reducing the voltage of the battery B3 below the value required to sustain a glow discharge within tube V and any one of the parallel tubes N3, N4 and N5 previously ionized.

When one of the input circuits such as L3 receives a large alternating current potential which is, of course, transmitted through the transformer T3 to the cathodes F1 and F2 of the tube N3 and if this potential effect should break down the gap within that tube and produce a glow discharge therein, it is to be noted that no reaction will be produced in the input circuits L4 and L5 which are coupled to the tubes N4 and N5 connected in parallel with the tube N3. Hence it follows that any one of the three circuits La, L4 and L5 may be used to trigger off the relay arrangement or work circuit designated L2 through the tube V and through the tubes N3, N4 or N5 associated with the input circuit receiving the high voltage, and

' while this occurs, no eiect will be produced in the other input circuits which are not impressed with such high voltages. It will be apparent also that none of the voltage of batteries B2 or B3 will be transmitted back through any of the transformers T3, T4 and T5 to the circuits which are not supplied with high voltage suflicient to break down the gaps of their associated tubes N3, N4 and N5, respectively.

While this invention has been shown and described in certain particular arrangements merely for the purpose of illustration, it will be understood that this invention may be applied to other and widely varied organizations without departing from the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. The combination of a first gas-filled tube having two cathodes and an anode, a second gaslled tube having a heater, a cathode, a grid and an anode, the cathodes of the first tube being connected to each othcr and to the grid of the second tube, a battery connected between the anode of the second tube and its cathode, a point intermediate to the terminals of the latter battery being connected to the anode of the rst tube, a

resistance, and a biasing battery connected in series with said resistance between the grid and cathode electrodes of the second tube.

2. The combination of an input circuit, a transformer, the primary winding of said transformer being connected to said input circuit, a rst gaslled tube having two cathodes and an anode, the secondary winding of said transformer being connected between the cathodes of said rst tube, a second gas-filled tube having a heater, a cathode, a grid and an anode, the midpoint of the secondary winding of said transformer being connected to the grid electrode of the second tube, a first battery, an output circuit connected in series with said first battery between the cathode and the anode of said second tube, a point intermediate to the terminals of the first battery being connected to the anode of the first tube, a resistance, and a second battery connected in series with said resistance between the grid and cathode of the second tube for biasing the grid to a high negative potential with respect to said cathode.

3. The combination of a first gas-filled tube having a cathode andan anode, the breakdown voltage of whichl is a small predetermined value, a second gas-lled tube having a cathode,V a grid and an anode, the breakdown voltage between the cathode and anode of which is a large, predetermined value, a source of potential of a value which equals or exceeds said large predetermined value which is connected between the cathode and anode of the second tube, the anode of the first tube being connected to a pointintermediate to the terminals of the source of potential, a resistance, and a second source of potential which is connected between the grid and cathode of the second tube through said resistance.

4. The combination of a control circuit, a circuit to be controlled, means for operating the circuit to be controlled only when the Voltage in the control circuit exceeds a predetermined value, said means comprising a cold cathode gas-filled tube having an anode and two cathodes, a hot cathode gas-filled tube, and aperiodic means for interconnecting said tubes between the control circuit and the circuit to be controlled so that the discharge gaps of both tubes may be simultaneously broken when the total alternating voltage in the control circuit exceeds the predetermined value.

5. Control apparatus comprising a cold cathode lgas-illed tube having an anode and two cathodes,

a hot cathode gas-filled tube connected in tandem with the cold cathode tube, means of aperiodic character for simultaneously breaking down the discharge gaps of both tubes when an alternating voltage exceeding a predetermined value reaches the cold cathode tube, and means for preventing the discharge gap of the hot cathode tube from being broken down except when the discharge gap of the cold cathode tube has broken down.

6. The combination of a plurality of cold cathode gas-,filled tubes connected in parallel with each other, each of said cold cathode tubes having an anode and two cathodes, a hot cathode gasi'llled tube, and means for breaking down the discharge gap of the hot cathode tube when the discharge gap of any one of the cold cathode tubes has broken down.

7. The combination of a plurality of parallel circuits which `are mutually non-reactive, a cold cathode gas-filled tube connected to each of said circuits, each cold cathode tube having an anode and two cathodes and being discharged when the total alternating voltage in the associated circuit exceeds a predetermined value, a hot cathode gas-nlled tube coupled to all of the cold cathode tubes, and means for discharging the hot cathode tube when any one of the cold cathode tubes has become discharged.

MOR'ION SULTZER. LELAND K. SWART. 

